DQB1 Loci Research Articles

Harmonisation of the HLA tests for the diagnosis of coeliac disease: experiences from the Czech external proficiency testing program.

Coeliac disease (CD) is an autoimmune disorder caused by the ingestion of gluten-containing grains. One of the prerequisites for the development of the disease is the presence of specific combinations of HLA alleles at the DQA1 and DQB1 loci. The HLA test is a supportive diagnostic test. In the Czech Republic, approximately 3,500 HLA tests for CD diagnosis are performed annually in almost three dozen laboratories. The HLA Department of the Institute of Haematology and Blood Transfusion in Prague has been offering the EPT "Detection of HLA Alleles Associated with Diseases" for more than 10years. The results are evaluated in terms of the correct determination of predisposing alleles/allelic groups and clinical interpretation. Every year, we notice some problems with the detection of CD-associated alleles and the interpretation of results. Annual workshops are part of this EPT, and they also include recommendations for the interpretation of results. This interpretation is evolving based on the current knowledge in the field. The current recommendation for interpretation was adopted in 2023, dividing HLA-DQA1/DQB1 genotypes into three categories: 1) detected HLA genotype is associated with predisposition to coeliac disease; 2) coeliac disease could not be excluded based on the detected HLA genotype; 3) coeliac disease could be excluded with high probability based on the detected HLA genotype. The quality of examination is increasing but still needs improvement. Correct results and accurate interpretation can inform clinicians' decisions about the diagnosis of coeliac disease in appropriate patients.

HLA alleles, haplotypes frequencies, and their association with hematological disorders: a report from 1550 families whose patients underwent allogeneic bone marrow transplantation in Egypt.

HLA alleles are representative of ethnicities and may play important roles in predisposition to hematological disorders. We analyzed DNA samples for HLA-A, -B, -C, -DRB1, and -DQB1 loci, from 1550 patients and 4450 potential related donors by PCR-SSO (Polymerase chain reaction sequence-specific oligonucleotides) and estimated allele frequencies in donors and patients from 1550 families who underwent bone marrow transplantation (BMT) in Egypt. We also studied the association between HLA allele frequencies and incidence of acute myeloid leukemia, acute lymphoblastic leukemia, and severe aplastic anemia. The most frequently observed HLA class I alleles were HLA- A*01:01 (16.9%), A*02:01 (16.1%), B*41:01 (8.7%), B*49:01 (7.3%), C*06:02 (25.1%), and C*07:01 (25.1%), and the most frequently observed class II alleles were HLA-DRB1*11:01 (11.8%), DRB1*03:01 (11.6%), DQB1*03:01 (27.5%), and DQB1*05:01 (18.9%). The most frequently observed haplotypes were A*33:01~B*14:02 ~ DRB1*01:02 (2.35%) and A*01:01~B*52:01~DRB1*15:01 (2.11%). HLA-DRB1*07:01 was associated with higher AML odds (OR, 1.26; 95% CI, 1.02-1.55; p = 0.030). Only HLA-B38 antigen showed a trend towards increased odds of ALL (OR, 1.52; 95% CI, 1.00-2.30; p = 0.049) HLA-A*02:01, -B*14:02, and -DRB1*15:01 were associated with higher odds of SAA (A*02:01: OR, 1.35; 95% CI, 1.07-1.70; p = 0.010; B*14:02: OR, 1.43; 95% CI, 1.06-1.93; p = 0.020; DRB1*15:01: OR, 1.32; 95% CI, 1.07-1.64; p = 0.011). This study provides estimates of HLA allele and haplotype frequencies and their association with hematological disorders in an Egyptian population.

Uncommon HLA Alleles Observed in a Population of Istanbul Province

Objective: New polymorphisms are formed in human leucocyte antigen (HLA) genes with point mutations, gene conversions, and duplication, and the diversity continues to increase. Various new HLA alleles have significant roles in transplantation, and epidemiologic and population studies. The aim of our study was to determine the status of HLA alleles in the Turkish population, which is uncommon, well-defined, and non-defined in the world population according to the international ImMunoGeneTics information system® (IMGT) database. Methods: We performed HLA-A, -B, -C, -DQB1, and DRB1 loci at the four-field resolution level, using Sanger- sequence-based typing (SBT) for 5592 healthy, unrelated bone marrow donor volunteers from Istanbul Province. The uncommon alleles were also confirmed using high-throughput next-generation sequencing (NGS). Results: Uncommon alleles were determined at five loci as follows: HLA-A*01:155, 02:66, 02:90, 02:110, 02:343, 03:82, 24:28, 24:146, 24:276, 24:356, 31:23,33:33, 68:38; HLA-B *07:240, 18:19, 35:193, 40:303, 51:69, 51:169; HLA-C*04:39, 06:40, 07:93, 12:149, 15:73; HLA-DRB1*11:149, 13:14:02 and HLA-DQB1*03:27. All alleles were arranged according to the common and well‐documented (CWD) 3.0.0 catalog. Conclusion: This is the first study to show uncommon alleles in our population. These reported data increase the knowledge of HLA polymorphisms in the Turkish population and provide a basis for further studies in population genetics. This information may also be useful in determining whether a matched, unrelated donor is unlikely to be found so that a mismatch strategy, an extended family search, or alternate therapy, can be pursued, thus saving time and cost for patients.

Effect of HLA Genotype on Anti-PD-1 Antibody Treatment for Advanced Renal Cell Carcinoma in the SNiP-RCC Study.

Immune checkpoint blockade therapies are widely used for cancer treatment, including advanced renal cell carcinoma (RCC). This study aimed to investigate the impact of zygosity in HLA genes and individual HLA genotypes on the efficacy of an anti-PD-1 Ab, nivolumab, in treating advanced RCC. Patient enrollment was conducted across 23 institutions in Japan from August 19, 2019, to September 30, 2020, with follow-up concluding on March 31, 2021. HLA genotype imputation of HLA-A, B, and C, DQB1, and DRB1 loci was performed. Among 222 patients, the presence of at least one homozygosity of the HLA-II allele significantly improved the best objective response (hazard ratio, 0.34; 95% confidence interval, 0.21-0.96; p = 0.042). The HLA evolutionary divergence (HED) of the HLA-A and HLA-B loci was higher than the HLA-C (p < 0.0001 and p < 0.0001, respectively), with high HED of the HLA-B locus correlating to clinical benefits in nivolumab treatment (hazard ratio, 0.44; 95% confidence interval, 0.21-0.90; p = 0.024) and improving cancer-specific survival compared with the low group (p = 0.0202). Additionally, high HED of the HLA-B locus was correlated with the number of infiltrated CD8+ cells in the tumor microenvironment (correlation coefficient, 0.4042). These findings indicate that the diversity of the HLA-B locus plays a significant role in the anti-tumor effect of nivolumab treatment in advanced RCC, potentially offering insights for improved risk stratification in nivolumab treatment and leading to better medical management of advanced RCC.

The Polymorphism Analysis of HLA Class II Alleles Based on Next-Generation Sequencing and Prevention Strategy for Allele Dropout

To investigate the accuracy of next-generation sequencing technology (NGS) in detecting the polymorphisms of HLA-DRB1, DQB1, DQA1, DRB3, DRB4, DRB5, DPA1 and DPB1 alleles in randomly-selected unrelated healthy individuals from Shenzhen Han population, investigate the potential reason for HLA-DRB1 allele dropout in routine NGS, and establish an internal quality control system. NGS-based HLA class II genotyping was performed on 1 012 samples using the MiSeqDxTM platform. The suspected missed alleles indicated by the quality control software and HLA-DRB1 homozygotes were confirmed by PCR-SSOP or PCR-SBT methods. A total of 139 alleles were detected, including HLA-DRB1(45), DRB3(7), DRB4(5), DRB5(7), DQA1(17), DQB1(21), DPA1(10) and DPB1(27). HLA-DRB1*09:01(17.09%),15:01(10.72%); DRB3*02:02(25.99%),03:01(10.18%); DRB4*01:03(36.46%); DRB5*01:01(15.42%); DQA1*01:02(20.01%),03:02(17.19%); DQB1*03:01(19.47%),03:03(17.98%), 05:02(11.66%), 06:01(10.67%); DPA1*02:02(54.45%), 01:03(31.18%) and DPB1*05:01(39.13%), 02:01(16.90%) alleles were the most common alleles in Shenzhen Han population (frequencies >10%). There was no statistical difference between the gene frequencies of HLA-DRB1 and DQB1 loci in our study. The HLA Common and Well-Documented Alleles in China (CWD2.4) (χ2=12.68, P >0.05). 94 cases of HLA-DRB1 homozygous samples detected by NGS were retested by PCR-SSOP or SBT method, and one case of allele dropout at HLA-DRB1 locus was found. SBT method confirmed that the allele of DRB1*04:03 was missed. The laboratory internal quality control system was established. Two cases of new alleles were detected and named by WHO Nomenclature Committee for Factors of the HLA System. The HLA genotyping results based on NGS showed a significantly lower ambiguity rate. The HLA class II alleles exhibit genetic polymorphism in the Han population of unrelated healthy individuals in Shenzhen. The independent method based on NGS in clinical histocompatibility testing has limitations and requires internal quality control strategies to avoid allele-dropout events.

The Influence of HLA Polymorphisms on the Severity of COVID-19 in the Romanian Population.

In this study, we aimed to investigate whether specific HLA alleles found in patients from Romania and the Republic of Moldova were associated with the severity of COVID-19 infection and its associated mortality. We analyzed the HLA alleles at the -A, -B, -C, -DRB1, and -DQB1 loci in a cohort of 130 individuals with severe and extremely severe forms of COVID-19, including 44 individuals who died. We compared these findings to a control group consisting of individuals who had either not been diagnosed with COVID-19 or had experienced mild forms of the disease. Using multivariate logistic regression models, we discovered that the B*27 and B*50 alleles were associated with an increased susceptibility to developing a severe form of COVID-19. The A*33 and C*15 alleles showed potential for offering protection against the disease. Furthermore, we identified two protective alleles (A*03 and DQB1*02) against the development of extremely severe forms of COVID-19. By utilizing score statistics, we established a statistically significant association between haplotypes and disease severity (p = 0.021). In summary, this study provides evidence that HLA genotype plays a role in influencing the clinical outcome of COVID-19 infection.

DQB1 antigen matching improves rejection-free survival in pediatric heart transplant recipients

IntroductionPresence of donor-specific antibodies (DSAs), particularly to class II antigens, remains a major challenge in pediatric heart transplantation. Donor-recipient human leukocyte antigen (HLA) matching is a potential strategy to mitigate poor outcomes associated with DSAs. We evaluated the hypothesis that antigen mismatching at the DQB1 locus is associated with worse rejection-free survival. MethodsData was collected from Scientific Registry of Transplant Recipients for all pediatric heart transplant recipients 2010-2021. Only transplants with complete HLA typing at the DQB1 locus for recipient and donor were included. Primary outcome was rejection-free graft survival through 5 years. ResultsOf 5,115 children, 4,135 had complete DQB1 typing and were included. Of those, 503 (12%) had 0 DQB1 donor-recipient mismatches, 2,203 (53%) had 1, and 1,429 (35%) had 2. Rejection-free survival through 5 years trended higher for children with 0 DQB1 mismatches (68%), compared to those with 1 (62%) or 2 (63%) mismatches (pairwise p=0.08 for both). In multivariable analysis, 0 DQB1 mismatches remained significantly associated with improved rejection-free graft survival compared to 2 mismatches, while 1 DQB1 mismatch was not. Subgroup analysis showed the strongest effect in non-Hispanic Black children and those undergoing retransplant. ConclusionMatching at the DQB1 locus is associated with improved rejection-free survival after pediatric heart transplant, particularly in Black children, and those undergoing retransplant. Assessing high-resolution donor typing at the time of allocation may further corroborate and refine this association. DQB1 matching may improve long-term outcomes in children stabilized either with optimal pharmacotherapy or supported with durable devices able to await ideal donors.

Association of human leukocyte antigen (HLA) footprints with the comorbidity of latent autoimmune diabetes in adults (LADA) and hepatitis C virus (HCV) infection: A multicenter cross-sectional study

AimsThis study aims to investigate the interplay between hepatitis C virus (HCV) infection and major forms of diabetes: type 1 diabetes (T1D), type 2 diabetes (T2D), and latent autoimmune diabetes in adults (LADA). MethodsThis multicenter study analyzed a cohort of 2699 diabetic and 7344 non-diabetic subjects who visited medical centers in China from 2014 to 2021. T1D, T2D, LADA, and HCV were diagnosed using standard procedures. High-throughput sequencing was conducted to identify genetic footprints of human leukocyte antigen (HLA) alleles and haplotypes at the DRB1, DQA1, and DQB1 loci. ResultsHCV infection was detected in 3 % (23/766) of LADA patients, followed by 1.5 % (15/977) of T2D patients, 1.4 % (13/926) of T1D patients, and 0.5 % (38/7344) of non-diabetic individuals. HCV prevalence was significantly higher in people with diabetes than in non-diabetic individuals (p < 0.01). HLA alleles (DQB1*060101, DQB1*040101) and haplotypes (DRB1*080302-DQA1*010301-DQB1*060101) in LADA patients with HCV revealed higher frequencies than in LADA patients without HCV (adjusted p < 0.03). Furthermore, a higher risk of diabetes complications was found among LADA patients with HCV infection (p < 0.001). ConclusionsLADA patients are susceptible to HCV infection, potentially associated with certain HLA alleles/haplotypes. Early diagnosis and treatment of HCV infection among people with diabetes are important for the management of severe complications.

Changes in the Immunogenetic Landscape with the Age of Disease Onset in Acquired Aplastic Anemia and Paroxysmal Nocturnal Hemoglobinuria: An Analysis of a Cohort of Adult and Pediatric Patients from the French National Reference Center for Aplastic Anemia

Over the past decade, the role of HLA molecules in the pathophysiology of immune aplastic anemia (IAA) has been highlighted by the identification of somatic clonal losses of HLA molecules on leukocytes and the enrichment of certain HLA alleles in patients with AA compared to the general population. More recently, the analysis of the HLA Evolutionary Divergence (HED) score in a large US adult cohort showed that IAA patients were carrying class II HLA molecules whose antigen-binding sites were characterized by a high degree of structural homology and that low class II HED score was associated with a higher risk of malignant progression and poorer survival (Pagliuca et al., Blood, 2021). To evaluate these findings in an independent cohort, we conducted a retrospective study of a large cohort of adult and pediatric patients diagnosed with IAA and/or PNH included in 2 different centers in Paris from the French National Center for Aplastic Anemia (RIME observatory). Patients' 2-field HLA genotyping for HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1 loci and HLA-DQA1 genotype imputations were compared with those of a control cohort of 593 allogeneic donors in the context of hematologic malignancies. The MidasHLA R package was used to assess HLA-disease associations using logistic regression analysis with a dominant inheritance model (Benjamini-Hochberg adjusted p-values). HED metrics, used as a surrogate for the width of the immunopeptidome presented by the patient's HLA molecules (Pierini and Lenz, Mol. Biol. Evol., 2018) were calculated for the different HLA loci and for the entire HLA class I and HLA class II genes (mean of HED scores for the corresponding loci). The cohort consisted of 449 patients who were children (&amp;lt;15 years of age, n=130), adolescents and young adults (15-25 years of age, n= 141), and adults (&amp;gt; 25 years of age, n= 178) at the time of diagnosis. Fifty-five percent had IAA, 28% had AA with a PNH clone, 8% had hepatitis-associated AA and 9% had hemolytic PNH. The distribution of diagnoses differed across age groups, with a decreasing incidence of hepatitis-associated AA and an increasing incidence of both AA/PNH and PNH with age. We first confirmed a strong association between patients and the DRB1*15:01, DQB1*06:02 and DQA1*01:02 alleles (these 3 alleles being in strong linkage disequilibrium) in addition to a few additional alleles at the DPB1 and B loci (Figure 1). This finding was consistent with several published studies in populations of different ethnicities. Using stepwise conditional testing, we then showed that only DQB1*06:02 (and DPB1*01:01 to a much smaller extent) remained associated with the disease (OR=2.49, adjusted p-value = 7.55E-09). Interestingly, the DQB1*06:02 association was lost when analyzing the subset of pediatric patients. Among patients, we then demonstrated a strong correlation between the age at disease onset and the presence of the DQB1*06:02 (Figure 2, exact Fisher's test, p=0.0005), DQA1*01:02 (p= 0.006) and DRB1*15:01 alleles (p&amp;lt; 0.0001). Intriguingly, we additionally found an overrepresentation of the ancestral A*01:01 B*08:01 DRB1*03:01 haplotype among patients with primary PNH (14.6%) compared to both patients with AA/PNH (2.4%, p=0.009) and controls (6.3%, p=0.083). Next, we investigated the HED metrics at the different HLA loci. There was no significant decrease in HED scores in patients compared to control, either at the DQB1, DQA1 and DRB1 loci or for the overall HED Class II score (mean value of HED-DRB1, -DQB1 and -DPB1), even in the subsets of DRB1*15:01 or DQB1*06:02 non-carriers. This result differed from the aforementioned US study, likely due to differences in geographic inclusion areas between the 2 cohorts. To rule out bias due to the inclusion of pediatric patients in our cohort, we then focused on the adult-onset subgroup and observed similar results. However, considering the entire cohort and despite no differences between patients and controls, we identified a strong association between age at onset and HED-B and HED-Class I (mean value of HED-A, -B and -C), with the divergence increasing with age (Kendall correlation test, p=0.001 and p=0.007, respectively). Taken together, these results highlight different immunogenetic landscapes according to the age of disease onset. We can hypothesize that the immune-mediated pathophysiological mechanisms may differ with age with a preponderant role of DQB1*06:02 appearing at later age of disease onset.

The Protective Effect of HLA-DRB1 and HLA-DQB1 Alleles to ACPA-Positive and RF-Positive RA in Albanian Population

BACKGOUND: The prevalence of rheumatoid arthritis (RA) and its specific autoantibodies varies in different populations. This variability depends on the genetic polymorphism of the immune response genes among which the HLA system plays a major role. AIM: We conducted a preliminary study of the distribution of HLA-DRB1 and HLA-DQB1 first field level alleles in a sample of 100 Albanian patients with RA. METHODS: In this context, we studied the HLA-DRB1 and HLA-DQB1 first-level allele frequencies in 100 Albanian patients with RA and considering their rheumatoid factor (RF) and anti-citrullinated peptide antibodies (ACPA) serologic subgroups. We compared them with the respective frequencies in a population of 191 Albanian individuals without known pathology. RESULTS: No differences were found between the controls and the RA patient group, but three statistically significant differences were found: an increase in DRB1*04 among ACPA-positive, RF-positive and ACPA-positive/RF-positive patients, a significant decrease in DRB1*11 among ACPA-positive/RF-positive, and also a decrease in DRB1*13 among RF-positive patient subgroups. The frequencies of DRB1 allotypes in ACPA+ and RF+ patients compared to their counterpart ACPA− and RF−patient subgroups showed the predisposing effect of HLA-DRB1*04 for ACPA and RF seropositivity (p, respectively, 0.0008 and 0.0017) and the protective role of HLA-DRB1*11 for ACPA and RF positivity (p, respectively, 0.007 and 0.02). The same protective role from the RF positivity is also found with the HLA-DRB1*13 alleles (p = 0.007). As far as the DQB1 locus is concerned, a protective association has been found between the HLA-DQB1*06 alleles with both RF+ and RF+ ACPA+ positivity (p, respectively, 0.05 and 0.04) when comparing the control group with the respective RA patient subgroups. In ACPA+ and RF+ patients compared to the ACPA− and RF− patient subgroups, the only detected difference was between RF (+) and RF (−) patients (p =0.04). CONCLUSION: The relatively low frequencies of DRB1*04 and high (DRB1*11 and DRB1*13) in the Albanian population might explain the rather low positivity rate of ACPA and RF antibodies among the Albanian RA patients. Our study demonstrates that DRB1*11, DRB1*13 and DQB1*06 may be negatively associated with RA. Conversely, DRB1*04 may confer susceptibility to RA in Albanian population.

Maternal microchimerism in a 2-years old boy with IL2R gamma chain deficiency

BackgroundAccording to the literature, 40% of patients with SCID have maternal microchimerism. MethodsWe reported a case of a 2-year-old boy with X-linked SCID caused by a mutation in the IL2RG gene. ResultsTo search for a donor and subsequent HSCT, HLA genotyping of leukocytes from peripheral blood for class I and II by SBT method was performed. The HLA-I results were as follows: A*02:01,03:01,B*07:02,18:01, C*05:01,07:02. The results for class II were questionable, as an additional allele was identified at the DQB1 locus.To exclude contamination, typing was carried out with another sample of leukocytes. The result was a complete confirmation of the primary data for class I; for class II, the result could not be interpreted. To exclude the admixture of maternal lymphocytes in the patient’s peripheral blood samples, HLA genotyping of the buccal epithelium was performed: it turned out to be impossible to identify alleles at the DQB1 and DRB1 loci. Subsequently, it turned out that the child was periodically breastfed, which could cause the presence of maternal cells in the buccal epithelium.From all of the above, it is likely that problems in identifying the patient’s HLA genotype could be related to the phenomenon of maternal microchimerism.To differentiate chimerism from mosaicism, a molecular genetic analysis of STR loci of the patient and his parents was performed. The results demonstrated that the patient’s blood sample contained an admixture of maternal cells, indicating the presence of maternal microchimerism. Molecular genetic study data confirmed the results of cytogenetic analysis by FISH. The study of lymphocytes from the patient’s peripheral blood and bone marrow revealed that 49% and 92% of the cells, respectively, had a karyotype XX. Buccal epithelium was examined to exclude the constitutional nature of mosaicism by sex chromosomes: it was found that all buccal epithelial cells had a karyotype XY.After the results of the cytogenetic study, we repeated HLA typing of buccal epithelium DQB1 and DRB1 loci. The following results were obtained during genotyping: DRB1*03:01,11:01,DQB1*02:01,03:01, thus the patient’s HLA genotype was established.Results of the analysis of short tandem repeats (STR loci) of the patient and his parentsStudied loci DNABlood sampleBuccal epithelium sample of patientfather№allele/№allelemothers№allele/№allelepatient№allele/№allelefor a period of breastfeeding№allele/№allelewithout maternal cells№allele/№alleleD3S135815/1714/1814/17/18*14/17/18*14/17vWA17/1717/1917/17/19*17/17/19*17/17D16S53910/1311/1210/11/12*10/11/12*10/11D2S133821/2418/2518*/21/2518*/21/2521/25amelogeninXYXXXYXYXYD8S117912/1210/1210/1210/1210/12D21S1129/3029/30.229/30/30.2*29/30/30.2*29/30D18S5111/1812/1811/12*/1811/12*/1811/18D19S43315/1614/1514*/15/1514*/15/1515/15TH016/97/76/76/76/7FGA22/2421/2221/22*/2421/22*/2421/24*additional allele.Results of HLA-genotyping of the patient and his parentsInvestigation of the HLA- lociGenotype of the fatherGenotype of the motherGenotype of the patientHLA-AA*03:01, 24:02A*02:01, 23:01A*02:01, 03:01HLA-BB*07:02,15:17B*18:01, 51:01B*07:02,18:01HLA-CC*07:01, 07:02C*05:01,15:02C*05:01, 07:02HLA-DRB1DRB1* 11:01, 11:03DRB1* 01:01, 03:01DRB1* 03:01, 11:01HLA-DQB1DQB1* 03:01, 03:01DQB1* 02:01, 05:01DQB1* 02:01, 03:01 ConclusionsThe presence of maternal microchimerism can make it difficult to perform HLA genotyping in patients with SCID.

HLA amino acid Mismatch-Based risk stratification of kidney allograft failure using a novel Machine learning algorithm

ObjectiveWhile associations between HLA antigen-level mismatches (Ag-MM) and kidney allograft failure are well established, HLA amino acid-level mismatches (AA-MM) have been less explored. Ag-MM fails to consider the substantial variability in the number of MMs at polymorphic amino acid (AA) sites within any given Ag-MM category, which may conceal variable impact on allorecognition. In this study we aim to develop a novel Feature Inclusion Bin Evolver for Risk Stratification (FIBERS) and apply it to automatically discover bins of HLA amino acid mismatches that stratify donor-recipient pairs into low versus high graft survival risk groups. MethodsUsing data from the Scientific Registry of Transplant Recipients, we applied FIBERS on a multiethnic population of 166,574 kidney transplants between 2000 and 2017. FIBERS was applied (1) across all HLA-A, B, C, DRB1, and DQB1 locus AA-MMs with comparison to 0-ABDR Ag-MM risk stratification, (2) on AA-MMs within each HLA locus individually, and (3) using cross validation to evaluate FIBERS generalizability. The predictive power of graft failure risk stratification was evaluated while adjusting for donor/recipient characteristics and HLA-A, B, C, DRB1, and DQB1 Ag-MMs as covariates. ResultsFIBERS’s best-performing bin (on AA-MMs across all loci) added significant predictive power (hazard ratio = 1.10, Bonferroni adj. p < 0.001) in stratifying graft failure risk (where low-risk is defined as zero AA-MMs and high-risk is one or more AA-MMs) even after adjusting for Ag-MMs and donor/recipient covariates. The best bin also categorized more than twice as many patients to the low-risk category, compared to traditional 0-ABDR Ag mismatching (∼24.4% vs ∼ 9.1%). When HLA loci were binned individually, the bin for DRB1 exhibited the strongest risk stratification; relative to zero AA-MM, one or more MMs in the bin yielded HR = 1.11, p < 0.005 in a fully adjusted Cox model. AA-MMs at HLA-DRB1 peptide contact sites contributed most to incremental risk of graft failure. Additionally, FIBERS points to possible risk associated with HLA-DQB1 AA-MMs at positions that determine specificity of peptide anchor residues and HLA-DQ heterodimer stability. ConclusionFIBERS’s performance suggests potential for discovery of HLA immunogenetics-based risk stratification of kidney graft failure that outperforms traditional assessment.

The polymorphism of HLA class I and II alleles in Indian patient with thalassemia

Numerous HLA allele relations with various diseases have been observed all over the world, including leukemia, aplastic anemia, and thalassemia. The current study looked at the frequency of HLA A, B, C, DRB1, and DQB1 loci with thalassemia to see if there was a correlation between the HLA allele and the disease. The study involved a total of 200 patients (cases) and 200 healthy people (controls). Using a polymerase chain reaction sequence-specific oligonucleotide probe technique, all of these samples were HLA typed for HLA class I (A, B, C loci) and class II (DRB1 and DQB1 loci). HLA-DRB1*15:02 (p = 0.0395400, OR = 2.288) and DQB1*06:01 (p = 0.00056000, OR = 2.248911) were found to have a positive connection with thalassemia. Whereas, HLA-A*31:01 (p = 0.0361200, OR = 0.202), B*07:02 (p 0.0358530, OR = 0.296), B*08:01 (p = 0.04595400, OR = 0.476), C*07:02 (p = 0.000240000, OR = 0.00001,) and HLA-DQB1*06:03 (p = 0.007966000, OR = 0.395) were seen to be negatively associated. Our findings are the first to indicate an association between thalassemia and HLA alleles (A, B, C, DRB1, and DQB1 alleles) in the Indian population, and they can be used to strengthen thalassemia studies.

Haplotype-dependent HLA-DRB1-DQB1 susceptibility to occult HBV infection in Xi'an Han population.

Occult hepatitis B virus (HBV) infection (OBI) is primarily characterized by the persistence of HBV-DNA in the liver tissues and/or in the serum without detectable HBsAg. Human leukocyte antigen (HLA) polymorphisms have been found to be strongly associated with HBV in different ethnic backgrounds. The association of HLA-DRB1-DQB1 haplotypes with OBI has not been previously reported in China. The aim of this study was to identify the potential association of HLA-DRB1-DQB1 haplotypes that may be involved in OBI genetic susceptibility. A case-control study was conducted between 107 OBI subjects and 280 healthy controls from the blood donors in the Shaanxi Province Blood Center. The HLA-DRB1, DQB1 loci were genotyped using polymerase chain reaction-sequence based typing (PCR-SBT). Based on the genotype data of the two loci, haplotype estimation was performed. HLA-DRB1*07:01-DQB1*02:02 (pc=0.344 × 10-3 , OR=3.489, 95%CI=2.000-6.088) and HLA-DRB1*09:01-DQB1*03:03 (pc=0.02, OR=2.370, 95%CI=1.450-3.873) serve as the possible risk and susceptibility haplotypes for OBI in Xi'an Han after Bonferroni correction. This study demonstrated that HLA II haplotypes were significantly associated with OBI in the Xi'an Han population. To the best of our knowledge, this is the first study to associate HLA-DRB1-DQB1 haplotypes with OBI, which can provide valuable insights into the relationship between the various genetic factors and immune responses in the Xi'an population. The findings can also form the basis for future studies about the role of HLA in OBI.

Molecular disparity of HLA-DPB1 is associated with the development of subsequent solid cancer after allogeneic hematopoietic stem cell transplantation.

An increased incidence of subsequent solid cancers (SSCs) has been reported in long-term survivors of allogeneic hematopoietic stem cell transplantation (allo-HSCT), and SSC is associated with inferior mortality and morbidity. Previous studies showed that the incidence of SSC is significantly higher in those who underwent allo-HSCT from HLA-mismatched donors, suggesting that persistent alloimmunity may predispose patients to SSCs. It was recently reported that, in a cohort of patients who received allo-HSCT from an unrelated donor matched at HLA-A, -B, -C, -DRB1/3/4/5, and -DQB1 loci, HLA-DPB1 alloimmunity determined by high mismatched eplets (MEs) and Predicted Indirectly Recognizable HLA Epitopes (PIRCHE) score (PS), was associated with relapse protection and increased risk of acute graft-versus-host disease (GVHD). In the present study, the impact of HLA-DPB1 alloimmunity assessed by molecular mismatch algorithms on the development of SSCs in a cohort of 1514 patients who underwent allo-HSCT for hematologic malignancies was further investigated. ME load at the HLA-DPB1 locus was measured using the HLAMatchmaker module incorporated in HLA Fusion software, and the PS for mismatched HLA-DPB1 was calculated using the HSCT module from the PIRCHE online matching service. In multivariable analysis after adjusting for baseline risk factors, higher ME, PS-I, and PS-II in the GVH direction, but not in the HVG direction, were associated with an increased risk of SSCs (ME: subdistribution hazard ratio [SHR] 1.58, p= .01; PS-I: SHR 1.59, p= .009; PS-II: SHR 1.71, p= .003). In contrast, nonpermissive HLA-DPB1 mismatches defined by the conventional T-cell epitope algorithm were not predictive of the risk of SSCs. Moreover, posttransplant cyclophosphamide-based GVHD prophylaxis was associated with a reduced risk of subsequent solid cancer (SHR 0.34, p= .021). These results indicate for the first time that increased GVH alloreactivity could contribute to the development of SSCs in allo-HSCT survivors.

HLA Class I Association With Autoimmune Diabetes in Chinese People: Distinct Implications in Classic Type 1 Diabetes and LADA.

We aimed to investigate whether human leukocyte antigen (HLA) Class I loci differentially modulated the risk for and clinical features of Chinese people with classic type 1 diabetes (T1D) and latent autoimmune diabetes in adults (LADA). In this case-control study, genotypes of HLA-A, -B, -C, -DRB1, -DQA1, and -DQB1 loci were obtained from 1067 cases with classic T1D, 1062 cases with LADA, and 1107 normal controls using next-generation sequencing. Despite 4 alleles shared between classic T1D and LADA (protective: A*02:07 and B*46:01; susceptible: B*54:01 and C*08:01), 7 Class I alleles conferred risk exclusively for classic T1D (A*24:02, B*15:02, B*15:18, B*39:01, B*40:06, B*48:01, and C*07:02) whereas only A*02:01 was an additional risk factor for LADA. Class I alleles affected a wide spectrum of T1D clinical features, including positive rate of protein tyrosine phosphatase autoantibody and zinc transporter 8 autoantibody (A*24:02), C-peptide levels (A*24:02), and age at diagnosis (B*46:01, C*01:02, B*15:02, C*07:02, and C*08:01). By contrast, except for the detrimental effect of C*08:01 on C-peptide concentrations in LADA, no other Class I associations with clinical characteristics of LADA could be reported. The addition of Class I alleles refined the risk model consisting only of DR-DQ data in classic T1D while the overall predictive value of the LADA risk model comprising both Class I and II information was relatively low. The attenuated HLA Class I susceptibility to LADA was indicative of a less deleterious immunogenetic nature compared with classic T1D. These autoimmune diabetes-related Class I variants might serve as additional markers in future screening among Chinese people.

Distributions of the HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1 alleles and haplotype frequencies of 1763 stem cell donors in the Colombian Bone Marrow Registry typed by next-generation sequencing.

The HLA compatibility continues to be the main limitation when finding compatible donors, especially if an identical match is not found within the patient's family group. The creation of bone marrow registries allowed a therapeutic option by identifying 10/10 compatible unrelated donors (URD). However, the availability and frequency of haplotypes and HLA alleles are different among ethnic groups and geographical areas, increasing the difficulty of finding identical matches in international registries. In this study, the HLA-A, -B, -C, -DRB1, and -DQB1 loci of 1763 donors registered in the Colombian Bone Marrow Registry were typed by next-generation sequencing. A total of 52 HLA-A, 111 HLA-B, 41 HLA-C, 47 HLA-DRB1, and 20 HLA-DQB1 alleles were identified. The 3 most frequent alleles for each loci were A*24:02g (20,8%), A*02:01g (16,1%), A*01:01g (7.06%); B*35:43g (7.69%), B*40:02g (7.18%), B*44:03g (6.07%); C*04:01g (15.40%), C*01:02g (10.49%), C*07:02g (10.44%); DRB1*04:07g (11.03%), DRB1*07:01g (9.78%), DRB1*08:02g (6.72%); DQB1*03:02g (20.96%), DQB1*03:01g (17.78%) and DQB1*02:01g (16.05%). A total of 497 HLA-A-C-B-DRB1-DQB1 haplotypes were observed with a frequency greater than or equal to 0.05% (> 0.05%); the haplotypes with the highest frequency were A*24:02g~B*35:43g~C*01:02g~DQB1*03:02g~DRB1*04:07g (3.34%), A*29:02g~B*44:03g~C*16:01g~DQB1*02:01g~DRB1*07:01g (2.04%), and A*01:01g~B*08:01g~C*07:01g~DQB1*02:01g~DRB1*03:01g (1.83%). This data will allow the new Colombian Bone Marrow Donor Registry to assess the genetic heterogeneity of the Colombian population and serve as a tool of interest for future searches of unrelated donors in the country.

Association of human leukocyte antigen class II alleles with epithelial cell apoptosis and extracellular matrix production in acute COVID-19.

Pathogenic mechanisms and long-term consequences of COVID-19 require attention in studies on SARS-CoV-2. The association of the severity of COVID-19 with genetic factors, such as human leukocyte antigen (HLA) genes, remains underexplored. Our study assessed the relationships between HLA class II alleles and COVID-19 severity and blood-based indicators of systemic inflammation and organ damage, serum markers of epithelial cell apoptosis such as caspase-cleaved CK18 fragment M30 (CK18-M30) and the extracellular matrix product hyaluronic acid (HA). The study included 101 hospitalized COVID-19 patients (mean age 60 ±14 years). Clinical tests were performed at admission to the hospital. The levels of CK18-M30 and HA were detected in serum by enzyme-linked immunosorbent assay (ELISA). HLA typing was performed in HLA-DRB1, -DQA1, and -DQB1 loci by the polymerase chain reaction with low-resolution sequence-specific primers. Sixty-one patients had a non-severe and 40 had a severe or critical disease course (following the WHO definition). The severity was associated with older age, male gender, higher HA, CK18-M30, and some indicators of inflammation. Despite the lack of direct association between HLA alleles and the severity of COVID-19, the presence of HLA-DRB1*04 and 12 alleles in the genotype was associated with lowered or elevated HA, respectively. The HLA-DQB1*03:01 allele was associated with lowered CK18-M30, aspartate aminotransferase, and ferritin. In addition, HLA-DQB1*06:01 was associated with elevated alanine aminotransferase. Associations of HLA class II alleles with markers of epithelial cell apoptosis and extracellular matrix production indirectly support the influence of HLA genes on acute COVID-19 severity.

HLA antigen and HLA eplet mismatches - important factors for developing donor-specific antibodies after kidney transplantation

Kidney donor-recipient mismatches (MM) in human leukocyte antigen (HLA) system can have the impact on graft survival as de novo formation of donor-specific HLA antibodies (DSA) post-transplant can increase the risk of acute and chronic rejections. Eplets, the smallest functional units of epitopes, are in recent years also being considered in recipient-donor matching. We have retrospectively analysed the relationship between MM at HLA-A, -B, -DRB1 and -DQB1 loci and the development of DSA in 47 kidney transplant recipients that were negative for the presence of HLA antibodies pre-transplant. A total of 19 patients (40%) developed DSA (DSA+) post-transplant, revealing sensitization to HLA class II MM antigens as the most prevalent (84% of DSA+ patients). MM at all HLA loci contributed to the development of HLA locus-specific antibodies, with the prevalence of HLA-DQ sensitization, as 41% of recipients with HLA-DQ MM developed DSA. HLAMatchmaker analysis for HLA-DR/DQ total eplet MM showed statistically significant difference between DSA- (N=33) and DSA+ recipients (N=14) for a total number of eplet MM (300 in DSA- vs 248 in DSA+; P=0.0004). These results emphasize the importance of HLA Class II matching in kidney transplantation.

Low-Dose Antithymocyte Globulin Plus Low-Dose Post-Transplant Cyclophosphamide for Prevention of Graft-Versus-Host Disease after Haploidentical Peripheral Blood Stem Cell Transplants: A Large Sample, Long-Term Follow-up Retrospective Study

Background: The use of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) to treat hematological diseases is increasing. Two regimens for in vivo T-cell depletion are currently used in haplo-HSCT for prophylaxis of graft-versus-host disease (GVHD), including anti-thymocyte globulin (ATG)-based and posttransplant cyclophosphamide (PTCy)-based regimens. Our previous studies have demonstrated that low-dose ATG plus low-dose PTCy (low-dose ATG/PTCy) combined with cyclosporine (CSA) and mycophenolate mofetil had promising activity for the prevention of GVHD in haploidentical peripheral blood stem cell transplantation (haplo-PBSCT). Now, the efficacy of the low-dose ATG/PTCy regimen for GVHD prevention in haplo-HSCT was evaluated in a large sample with a long-term follow-up. Methods: The patients undergoing haplo-PBSCT between May 2017 and June 2021 in our center were enrolled in the retrospective study. The study included a variety of hematological diseases, such as acute myeloid leukemia (AML, n=113), acute lymphoblastic leukemia (ALL, n=49), mixed phenotype acute leukemia (MPAL, n=4), myelodysplastic syndromes (MDS, n=18), chronic myeloid leukemia (CML, n=10), non-Hodgkin's lymphoma (NHL, 30) and multiple myeloma (MM, n=1). All patients received low-dose ATG/PTCy regimen for prophylaxis of GVHD including ATG 2.5 mg/kg administered on day −2 to −1 and cyclophosphamide (Cy) 50 mg/kg on day +3, cyclosporine A (CsA) and mycophenolate mofetil (MMF) initiating on day +4. The starting infusion dose of CsA was 2 mg/kg, after which the dose was modified to obtain a nadir serum level between 200 and 300 ng/ml, eventually tapering from day +90 to day +180. MMF was administered orally at 15 mg/kg three times daily (maximum dose of 3 g per day) until day +34 and discontinued if no aGvHD. Mycophenolic acid sodium enteric tablets (MPA) correspond to MMF instead. Grafts were from mobilized peripheral blood stem cells. Family members selected as haploidentical donors were defined on the HLA-A, -B, -C, -DRB1, and -DQB1 locus at the high-resolution level of the recipient donor number of human leukocyte antigen (HLA) mismatches >2. Results: Two hundred and twenty-five patients undergoing haplo-PBSCT were enrolled in the study. There were 144 males and 81 females with a median age of 38 years (range, 6 to 69 years). At the time of transplantation, 146 (64.89%, 146/225) patients were in complete response (CR), while 79 (35.11%, 79/225) patients had active disease. One hundred and five patients received myeloablative conditioning (MAC) regimens, while 40 patients received reduced-intensity conditioning (RIC) regimens. All patients received PBSC grafts with the median CD34+ cells of 10.3 (1.64-46.55) × 108/kg, and the median mononuclear cells (MNCs) was 15.35 (3.48-39.74) × 108/kg. Ten patients failed to engraft, including 6 patients with primary graft failure and 4 with secondary graft failure. The median time for neutrophil engraftment was 12 days (range, 9-28 days), while the median time for platelet engraftment was observed in 13 days (range, 9-87 days). The cumulative incidence (CI) of grades I-IV acute GVHD (aGVHD) was 30.7% (24.6-36.9%). The CIs of grades II-IV and III-IV acute GVHD by 100 days post-transplant were 12.4% (95%CI, 8.0-16.8%) and 4.6% (95%CI, 1.8-7.4%), respectively. While chronic GVHD was 31.2% (95%CI, 24.6-37.9%) and moderate/severe chronic GVHD was 16.4% (95%CI, 11.1%-21.7%). A total of 90 patients died. Fifty-nine patients died of non-relapse causes (NRM 59/225, 26.2%). With a median follow-up of 26 months (range, 0-61 months), 50 cases relapsed. The median time of relapse was 15.5 months (range, 1−46 months). The mean OS and DFS were 38.01 months (95%CI, 34.33-41.6%) and 35.45 months (95%CI, 31.75-39.15%). The 2-year disease-free survival (DFS), overall survival (OS), and GVHD-free, relapse-free survival (GRFS) was 54.8% (95%CI, 48.94-62.26%) and 60.9% (95%CI, 54.24-67.56%) and 48.0% (95%CI, 41.14-54.86%), respectively. The 2-year CI of relapse was 26.6% and NRM was 16.6%. All patients were included in immune reconstitution studies and 81 cases were analyzed at each endpoint. On days +120, median CD3+, CD4+, CD8+, CD19+ and CD56/CD16+ counts were 954 (95-4891), 180 (8-743),754 (73-4272), 34 (1-276) and 215 (19-2539)/μl, respectively. Conclusion: The low-dose ATG/PTCy regimen presented a high efficacy for prophylaxis of GVHD in haplo-PBSCT.